The Influence of Dormant Pruning (Heading Back) on Flower Formation and Fruit Development on Young Persimmon (Diospyros kaki L.) Trees

Abstract

Japanese persimmon fruits are borne laterally on current season's growth arising from mixed buds. The flower buds differentiate during the previous summer month like these of most other deciduous fruit trees. To promote branching and to direct shoot growth, unbranched (spring branch) and branched limbs resulting from the second flush of growth in summer (summer branch) on young persimmon trees are headed back during the dormant season. In this study, the influence of such pruning practices on flowering and fruit development during the following season was examined for cvs. Saijo, Izu and Matsumotowase-Fuyu.
1. More, and superior quality flower buds were formed on the distal five or six mixed buds on current season's growth derived from summer branches than were formed on comparable laterals from spring branches of short and moderate lengths.
2. Heading back of long branches in February forced new shoots below the pruning cuts which were fruitful the following year, whereas heading back short shoots to their mid-point resulted in rapidly growing, vigorous laterals on which the percent fruit set during the following season was low.
3. Laterals, arising from summer branches (summer cycle), which were allowed to elongate intact the previous season, set more fruits than did laterals derived from short intact spring branches. But because the fruit set was higher on laterals from summer branches, the mean fruit size was smaller than was that on laterals originating from spring branches. Although the fruits on summer branches were smaller, they attained the same degree of skin coloring and contained an equal amount of percent soluble solids content as the fruits did on spring branches.